With many theories floating around we went to the horses mouth:Our question to Transport NSW was;We have many requests to take children and their carer in our carers cars in child safety seats. Can you tell us what is the correct procedure regarding this as carers would take safety seats out of their cars and put them back again? I have looked at Australian Standards, and many other sites.and their response was:There has never been a requirement for all child seats to be fitted by an authorised fitter. It was always a strongly recommendation.People can fit their own child seats as long as they are fitted correctly as per seat manufacturer's instruction.The most important thing is that the child car seats must be fitted correctly every time it has been removed and refitted.